Composite Materials Based on Polytetrafluoroethylene with SiO2 and BaTiO3 Inorganic Fillers

Abstract

Polymer dielectric composites consisting of polytetrafluoroethylene, silicon dioxide and barium titanate mixed in various proportions were successfully synthesized by low-temperature sintering. The structure of the obtained composite samples was studied by the X-ray diffraction, the electron microscopy, and the weight method. Electrical characteristics (dielectric permittivity and losses) of samples were investigated at a frequency of 1 MHz. According to structural analysis, the synthesized samples are a mixture of amorphous polytetrafluoroethylene and silicon dioxide, and crystalline ferroelectric BaTiO₃, the ratio of which determines the electrical properties of the composites. Depending on the content of barium titanate, the studied samples show a permittivity from 4 to 6.5 with a dielectric loss level of 0.06–0.14. It is shown that the significant influence on the dielectric properties of the polytetrafluoroethylene/silicon dioxide/barium titanate system is exerted by heat treatment modes.